思路

• C++ 11，VS2019
• 使用了unique_lock，条件变量
• 条件变量的wait(), notify_one()
• wait()中使用了lambda表达式

代码

#include <iostream>
#include <vector>
#include <thread>
#include <list>
#include <mutex>

using namespace std;

bool flag = true;

class A
{
public:

    void print1()
    {
        while (true)
        {
            std::unique_lock<std::mutex> lock1(print_mutex);
            data_var.wait(lock1, [] {return flag; });
            cout << "thread: " << std::this_thread::get_id() << " print: " << "A" << endl;

            flag = false;
            data_var.notify_one();
        }
    }

    void print2()
    {
        while (true)
        {
            std::this_thread::sleep_for(std::chrono::seconds(1));

            std::unique_lock<std::mutex> lock2(print_mutex);

            data_var.wait(lock2, [] {return !flag; });
            cout << "thread: " << std::this_thread::get_id() << " print: " << "B" << endl;

            flag = true;
            data_var.notify_one();
        }
    }

private:

    std::mutex print_mutex;
    std::condition_variable data_var;
};


int main()
{
    A myobj_a;

    std::thread print1(&A::print1, &myobj_a);
    std::thread print2(&A::print2, &myobj_a);

    print1.join();
    print2.join();

    return 0;
}